1.)A term used in physics to describe the amount of information extracted from an electro-magnetic signal compared the information orginally introduced into that signal.
2.)term used by psuedo-erudites to describe the degree of usefulness found in communications by media, individuals or otherwise.

1.)Hey Jim, this stereo set up is fucked. I'm pumping out 200W but my system sounds like a transistor radio. That is one fucked up signal-to-noise ratio.

2.)Typically, a demogague actually benefits from non-sensical, contradictory and inflammatory statements and agendas. Ironically, the higher the signal-to-noise ratio, the more effective they become since any useful information would actually reign them in.

A postitive signal to noise ratio means the signal is louder than the noise. A negative signal to noise ratio means the noise is louder than the signal. Typically, the signal is speech, music, or whatever sound is being listened for.

The amount of screaming one generates, in proportion to the amount of real content they are communicating.

People who grow up in empty households (often with a lot of older people) feel as though noise and signal are in direct proportion, which causes them to pump more noise in the hopes of generating more signal.